Preliminary Remarks



1.1.Preliminary remarks

Woolis an important material that is used to produce the spun yarns.These yarns are then used in the production of the outer as well asthe mid layer clothing and jumpers. The purpose of using the wool inthe two layers is to provide consumers of the jackets and clothingwith warmth, especially during the cold seasons. The increase in theliving environments with controlled climate and the popularity of theconcept of active life has reduced the demand for heavy clothing.Consequently, the demand for the lighter clothing has gone up, whichhas created the need for the production of finer and stronger yarnthat is needed in the manufacturing of casual garments. The lightergarments can be worn throughout the year since they aretrans-seasonal. The possibility of advancing the production of theAustralian Merino wool in the future will depend on the ability ofthe textile industry to expand its use in fasted growing areas. Forexample, the demand for the wool will be maintained if the textileindustry will be able to use it in the production of trans-seasonalknitwear. Currently, the trans-seasonal knitwear is dominated bysynthetic and cotton fibers. Australia has a significant growthopportunity since it produces about 90 % of the total quantity of thesuperfine wool in the world (Rowe 2010 Swan 2010).

Thespecific properties of the yarn are determined by the features of thefiber, including its diameter and length [1, 2]. The optimum fiberlength and diameter can be obtained through selective breeding of theanimals. This leads to the production of fine fibers. The productionof superfine fiber from animals has increased in the past fewdecades. However, farmers in Australia have achieved an insignificantdecrease in the diameter (&lt 1 µm) of the fiber in a period offive years [8]. Trends indicate that there is a growing interest in afurther reduction of the wool diameter. The physical as well as themechanical features of the wool can also be modified through theoxidation/reduction treatments [9]. These chemical reactions havebeen opposed because they are not friendly to the environment.

Thepre-treatment of the fiber for shrink-resistance is considered as aviable alternative for the modification of fiber. For example, theprotease enzyme process can lead to a reduction in diameter of thefiber at about 1.5-2.0 μm [10]. The Enzymatic treatment of the fiberis considered to be environmentally friendly compared to the chemicalreaction. However, it is associated with a high risk of destructionof the surface of the fiber. The Optim™ is another chemicaltreatment technique that is used to stretch the fiber in order tomake it finer [11]. This method can result in the attainment of thedesired level of fineness (2-3 µm). However, it leads to thedegradation of cuticle scales and a reduction in the wet modulus dueto an increase in the level of softness, length, and the silk-likeluster [12, 13]. These side effects suggest that researchers shouldidentify a method that will lead to a reduction in diameter of thefiber without damaging it.

Theoverall quality and suppleness of the knitwear is attributed to thepremium value of yarns that are constructed from luxurious fibers,such as the superfine merino wool and cashmere (De Boos 2005a Wang,Wang &amp Liu 2003). The expansion of the application of wool inorder to reach the next-to-skin knitwear market requires theproduction of fiber that is appealing. This study will focus on thecorrelation between the length and diameter of the fiber since theyare the key determinants of the quality of yarns. The outcome of theresearch is expected to indicate the role of length and diameter offiber in the overall quality of yarns. This topic was selectedbecause the determination of an ideal combination of diameter andlength of the fiber will enable textile factories produce yarns witha superior quality.